1. Field of the Invention
The present invention relates to a foldable tent frame for coupling a tent cloth with the tent frame in an integral form. In particular, the present invention relates to a foldable tent frame for tension-supporting the tent cloth from all sides, which includes a plurality of rods each having protuberances on both ends thereof with an elliptical flat spring coupled with it, hinged straight joints each having a securing sleeve, and a hinged bent joint, so that the tent can be folded into a compact size so as to make it convenient to carry and store, and that the tent can be unfolded into a firm large tent in a simple manner by unfolding the frame.
2. Description of the Prior Art
A typical conventional tent is disclosed in French Patent 2,422,777 and British Patent 2136845A, and this conventional tent has a plurality of frame members which are inserted into connecting devices, so that the tent can be installed to the desired height.
The tent of this type is economically advantageous. However, when the tent is disassembled, the separated frame members are liable to be lost, while when the tent is installed, all the joints of the frame members have to be assembled one by one. Consequently, time and efforts are much expended, and a severe inconvenience is encountered.
In an attempt to overcome the above disadvantages, another tent is disclosed in U.S. Pat. No. 4,074,682, and in this tent, the frame members are connected in the form of hinges.
In this conventional tent, there is no apprehension that the frame members are lost, and the tent can be speedily installed compared with the tent using the connecting devices.
In this tent however, its fixing posture is not secure. That is, if the tent receives a biased pressure by wind, the hinges of the frame members can be folded inwardly, with the result that the frame member may fall down. Thus there is a problem in the postural stability.
There is still another tent which is disclosed in U.S. Pat. No. 1,846,496. In this conventional tent, in order to more securely fix the hinge portion of the frame member, a sleeve is fitted to a hinge portion across two joining segments, and a fixing rod is fitted to it. Further, a lever having a ratchet on the sleeve is installed by means of a spring.
The structure of this tent is very complicated, and therefore, the production cost is raised. Further, the frame can be unfolded in a state with the lever pressed, and therefore, the unfolding manipulation is inconvenient. Further, during the use of the tent, the user may be injured, or the tent cloth or the user's cloth may be damaged.
Particularly, the upper folding portion of a frame member consists of a simple hinge, and therefore, its strength for supporting the ceiling of the tent is weak. Further, a separate securing device should be disposed at the crest portion for maintaining the frame members in the horizontal posture, thereby further making the frame structure complicated.
In an attempt to overcome the above described disadvantages of the foldable tent, there is disclosed still another tent in Korean Utility Model 39753 and U.S. Pat. No. 4,750,509 which were granted to the present applicant. In this conventional tent, a ratchet is installed on a hinge portion between frame member segments by means of a spring. Thus, if the frame members are unfolded, the ratchet is automatically engaged with an engaging piece of the frame member, thereby fixing the frame member in a straight form.
This tent ensures a folding convenience and a postural stability. Once the tent is installed, the frame members are not bent against a wind pressure, and the tent can never be collapsed. Particularly, the upper segment of a frame member forms a certain angle relative to the lower segment of the frame member owing to a bending of a connecting tube of the hinge. Therefore, the roof of the tent is firmly supported, and therefore, a separate device is not disposed on the crest portion of the tent.
However, the spring of the hinge portion is exposed, and therefore, it is aesthetically undesirable. Further, the bottom parts of the frame members support the tent cloth by being inserted into bands which are sewed to the tent cloth like in the previous methods. Therefore, the frame members are easily separated from the tent cloth during the folding of the tent, this being a problem.
In the above described conventional tents, the structure of the hinge portion is complicated, and therefore, the commodity value is degraded. Further, human fingers are liable to be caught into the gap of the spring of the ratchet, and the upper bent portions of the frame members are weak, with the result that the tent supporting strength is weak. Further, the bottom parts of the frame members are inserted into the bands which are sewed to the tent cloth, and therefore, if the tent is oscillated, the frame members are liable to depart from the bands.
Further, in the conventional foldable tents, the segments of the frame members are joined either by providing a joint and a rod in each of them through an injection molding, or are joined by means of pins. Therefore, during a repair or replacement of a frame member, the total frame has to be replaced together, and therefore, losses in time and economy are significant. Further, the conventional foldable tents use elastic frame members so as to form dome shaped tents, and therefore, the frame members are too weak to support a large sized tent such as a family cabin tent or sun shelter or screen shelter.